Fluorescent compounds are widely used as labels in biology and medicine. Through many years of refinement a number of fluorescent compound properties have been found to be advantageous for applications such as protein and antibody labeling. These properties include 1) low non-specific binding, 2) good photostability, 3) ease of chemical modification to permit tuning of absorption and emission wavelengths, 4) good water solubility and 5) resistance to the formation of dimers and higher aggregate. Generally, to achieve the latter two properties, chemical modification of the core fluorescent compound structure is performed to attach charged and neutral water solubilizing residues. Most commonly, electronically charged groups, such as sulfonate (e.g. U.S. Pat. Nos. 5,268,486, and 5,486,616) and quaternary ammonium (e.g. U.S. Pat. No. 6,348,599), have been used to impart water solubility to fluorescent compounds but examples also exist in which neutral groups such as carbohydrates (e.g. U.S. Pat. No. 5,877,310) and polyethylene glycol residues (e.g. Devlin et al, Clin. Chemistry 1993, 39, 1939) have been used. Nearly all commercially available biological labels that make use of the charged groups employ the sulfonate group as a water solubilizing substituent. These labels can aggregate and thus reduce label efficacy. There remains a need in the art for improved fluorescent compounds.